1. Field of the Invention
The invention relates generally to a process for recovering boron values from waste streams comprising boric acid and combustible organic materials; and more particularly to a process for the burning of combustible organic materials in the presence of boric acid, thereafter separating and recovering boric acids from the products of combustion.
2. The Prior Art
Incineration and selective recovery of desired elements has long been known as an important part of waste treatment, particularly with respect to sewage. It is well known, for example, that the organic materials in sludges can be disposed of by incineration. Incineration reduces the waste materials to inert ash concomitantly producing gases and vapors, principally carbon dioxide and steam. It is well known that sewage sludges can be calcined under controlled conditions to form calcium oxide solids from the calcium carbonate values. A specific process for recovering calcium values from calcium and phosphate-bearing sludge was patented as U.S. Pat. No. 3,996,133. Such processes involve process means specific to the waste stream element combination or mixture for the recovery of desired materials, which are, for the most part non volatile.
Industrial waste streams containing more volatile compounds such as boric acid are not uncommon. Boric acid and combustible organic materials constitute a substantial portion of the waste stream of a commercial process for the preparation of cyclohexanol and cyclohexanone by boric acid catalyzed oxidation of cyclohexane. The loss of the boric acid is not only wasteful but it is environmentally unacceptable; causing extremely offensive air and surface water pollution. Prior art methods of recovery involve the so-called "wet air oxidation" a liquid phase oxidation process conducted under high pressure and consequently at considerable expense. An efficient atmospheric pressure disposal system with the recovery of boric acid in cyclohexane oxidation waste streams containing boric acid would be a significant advance in the art and is an object of this invention.